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如何使用陀螺仪和加速度计计算行驶距离？

发布于 2024-11-19 13:05:05 字数 83 浏览 10 评论 0原文

我想构建一个应用程序，使用陀螺仪+加速度计准确计算 iPhone 行驶的距离（不是长距离）。这里不需要GPS。

我应该如何解决这个问题？

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苏辞 2024-11-26 13:05:06

我尝试了一下并放弃了（深夜，似乎没有取得任何进展）。这是针对 Unity3d 项目的。

如果有人想从我停下来的地方继续，我很乐意详细说明所有这些东西的作用。

基本上在一些结果被证明是误报之后，我想我应该尝试使用低通滤波器对其进行过滤，然后尝试通过查找趋势来消除反弹，然后 (acc_x[i-1]+acc_x[i] )/2.

看来误报仍然来自倾斜，我试图将其删除。

如果此代码有用或引导您到达某个地方，请告诉我！

using UnityEngine;
using System.Collections.Generic;

/// <summary>
/// [email protected]
/// </summary>
public class AccelerometerInput : MonoBehaviour 
{

    Transform myTransform;
    Gyroscope gyro;
    GyroCam gyroCam;

    void Awake()
    {
        gyroCam= FindObjectOfType<GyroCam> ();
        myTransform = transform;
        if (SystemInfo.supportsGyroscope) {
            gyro = Input.gyro;
            gyro.enabled = true;
        }
    }

    bool shouldBeInitialized = false; 
    void Update () 
    {

        transform.Translate (GetAccelerometer ());// * Time.deltaTime * speed);

        //GetComponent<Rigidbody> ().AddForce (GetAccelerometer ());

    }

    public float speed = 10.0F;

    public Vector3 dir;
    public float f;
    Vector3 GetAccelerometer()
    {

        dir = Input.acceleration;

        dir.x *= gyro.attitude.x;
        dir.z *= gyro.attitude.z;

        if (Mathf.Abs (dir.x) < .001f)
            dir.x = 0;
        dir.y = 0;
        if (Mathf.Abs (dir.z) < .001f)
            dir.z = 0;

        RecordPointsForFilter (dir);

        //print ("Direction : " + dir.ToString("F7"));

        return TestPointsForVelocity();
    }

    Vector3[] points = new Vector3[20];
    int index;
    void RecordPointsForFilter(Vector3 recentPoint)
    {
        if (index >= 20)
            index = 0;
        points [index] = EvaluateTrend (recentPoint);;
        index++;
    }

    //try to remove bounces
    float xTrend = 0;
    float zTrend = 0;
    float lastTrendyX = 0;
    float lastTrendyZ = 0;
    Vector3 EvaluateTrend(Vector3 recentPoint)
    {

        //if the last few points were positive, and this point is negative, don't pass it along
        //accumulate points into a trend
        if (recentPoint.x > 0)
            xTrend += .01f;
        else
            xTrend -= .1f;

        if (recentPoint.z > 0)
            zTrend += .1f;
        else
            zTrend -= .1f;

        //if point matches trend, keep it
        if (xTrend > 0) {
            if (recentPoint.x > 0)
                lastTrendyX = recentPoint.x;
        } else  // xTrend < 0
            if (recentPoint.x < 0)
            lastTrendyX = recentPoint.x;

        if (zTrend > 0) {
            if (recentPoint.z > 0)
                lastTrendyZ = recentPoint.z;
        } else  // xTrend < 0
            if (recentPoint.z < 0)
                lastTrendyZ = recentPoint.z;

        return new Vector3( lastTrendyX, 0, lastTrendyZ);
    }

    Vector3 TestPointsForVelocity()
    {
        float x = 0;
        float z = 0;

        float xAcc = 0;
        float zAcc = 0;

        int successfulHits = 0;
        for(int i = 0; i < points.Length; i++)
        {
            if(points[i]!=null)
            {
                successfulHits ++;
                xAcc += points[i].x;
                zAcc += points[i].z;
            }
        }

        x = xAcc / successfulHits;
        z = zAcc / successfulHits;

        return new Vector3 (x, 0, z);

    }
}

I took a crack at this and gave up (late at night, didn't seem to be getting anywhere). This is for a Unity3d project.

If anyone wants to pick up where I left off, I would be happy to elaborate on what all this stuff does.

Basically after some of what turned out to be false positives, I thought I'd try and filter this using a low pass filter, then attempted to remove bounces by finding a trend, then (acc_x[i-1]+acc_x[i])/2.

It looks like the false positive is still coming from the tilt, which I attempted to remove..

If this code is useful or leads you someplace, please let me know!

using UnityEngine;
using System.Collections.Generic;

/// <summary>
/// [email protected]
/// </summary>
public class AccelerometerInput : MonoBehaviour 
{

    Transform myTransform;
    Gyroscope gyro;
    GyroCam gyroCam;

    void Awake()
    {
        gyroCam= FindObjectOfType<GyroCam> ();
        myTransform = transform;
        if (SystemInfo.supportsGyroscope) {
            gyro = Input.gyro;
            gyro.enabled = true;
        }
    }

    bool shouldBeInitialized = false; 
    void Update () 
    {

        transform.Translate (GetAccelerometer ());// * Time.deltaTime * speed);

        //GetComponent<Rigidbody> ().AddForce (GetAccelerometer ());

    }

    public float speed = 10.0F;

    public Vector3 dir;
    public float f;
    Vector3 GetAccelerometer()
    {

        dir = Input.acceleration;

        dir.x *= gyro.attitude.x;
        dir.z *= gyro.attitude.z;

        if (Mathf.Abs (dir.x) < .001f)
            dir.x = 0;
        dir.y = 0;
        if (Mathf.Abs (dir.z) < .001f)
            dir.z = 0;

        RecordPointsForFilter (dir);

        //print ("Direction : " + dir.ToString("F7"));

        return TestPointsForVelocity();
    }

    Vector3[] points = new Vector3[20];
    int index;
    void RecordPointsForFilter(Vector3 recentPoint)
    {
        if (index >= 20)
            index = 0;
        points [index] = EvaluateTrend (recentPoint);;
        index++;
    }

    //try to remove bounces
    float xTrend = 0;
    float zTrend = 0;
    float lastTrendyX = 0;
    float lastTrendyZ = 0;
    Vector3 EvaluateTrend(Vector3 recentPoint)
    {

        //if the last few points were positive, and this point is negative, don't pass it along
        //accumulate points into a trend
        if (recentPoint.x > 0)
            xTrend += .01f;
        else
            xTrend -= .1f;

        if (recentPoint.z > 0)
            zTrend += .1f;
        else
            zTrend -= .1f;

        //if point matches trend, keep it
        if (xTrend > 0) {
            if (recentPoint.x > 0)
                lastTrendyX = recentPoint.x;
        } else  // xTrend < 0
            if (recentPoint.x < 0)
            lastTrendyX = recentPoint.x;

        if (zTrend > 0) {
            if (recentPoint.z > 0)
                lastTrendyZ = recentPoint.z;
        } else  // xTrend < 0
            if (recentPoint.z < 0)
                lastTrendyZ = recentPoint.z;

        return new Vector3( lastTrendyX, 0, lastTrendyZ);
    }

    Vector3 TestPointsForVelocity()
    {
        float x = 0;
        float z = 0;

        float xAcc = 0;
        float zAcc = 0;

        int successfulHits = 0;
        for(int i = 0; i < points.Length; i++)
        {
            if(points[i]!=null)
            {
                successfulHits ++;
                xAcc += points[i].x;
                zAcc += points[i].z;
            }
        }

        x = xAcc / successfulHits;
        z = zAcc / successfulHits;

        return new Vector3 (x, 0, z);

    }
}

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寒冷纷飞旳雪 2024-11-26 13:05:06

(acc_x[i-1]+acc_x[i])/2 是一个低通滤波器，它是两个时间测量之间的平均值

也请看这里：http://www.freescale.com/files/sensors/doc/app_note/AN3397.pdf
页码：3

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原谅过去的我 2024-11-26 13:05:06

Navisens。

https://navisens.com/#how-work

这里是声明 - Navisens 正在申请专利的技术以独特的方式处理加速度计和陀螺仪数据来定位您的手机。

尝试了演示应用程序，该应用程序主要用于在初始位置和位置确定后无需定位服务或 WiFi 即可绘制移动地图。方向已设定。

iOS SDK - https://github.com/navisens/iOS-SDK

Android SDK - < a href="https://github.com/navisens/Android-SDK" rel="nofollow noreferrer">https://github.com/navisens/Android-SDK

注意：这不是开源

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撩起发的微风 2024-11-26 13:05:06

这是答案。之前有人问过。

有一个名为 RangeFinder 的应用程序可以做同样的事情（可用在应用商店）。

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原谅我要高飞 2024-11-26 13:05:05

这个问题背后的基本演算在表达式

在此处输入图像描述

（以及 y 和 z 位移的类似表达式）和基本几何是毕达哥拉斯定理

在此处输入图像描述

因此，一旦您的加速度计信号通过低通滤波器并按采样间隔 dt 及时分箱，您可以找到 x 中的位移（请原谅我的 C...）

float dx=0.0f;
float vx=0.0f;
for (int i=1; i<n; i++)
 {
   vx+=(acceleration_x[i-1] + acceleration_x[i])/2.0f*dt;
   dx+=vx*dt;
 }

，对于 dy 和 dz 也类似。这里

float acceleration_x[n];

包含从测量开始到结束在时间 0、dt、2*dt、3*dt、... (n-1)*dt 处的 x 加速度值。

要找到总位移，您只需做

dl=sqrt(dx*dx + dy*dy + dz*dz);

陀螺仪，这不是必需的，但如果您测量线性距离，您可以使用陀螺仪读数来控制设备的旋转不要太大。如果旋转太强，请让用户重新进行测量。

Basic calculus behind this problem is in the expression

enter image description here

(and similar expressions for displacements in y and z) and basic geometry is the Pythagorean theorem

enter image description here

So, once you have your accelerometer signals passed through a low-pass filter and binned in time with sampling interval dt, you can find the displacement in x as (pardon my C...)

float dx=0.0f;
float vx=0.0f;
for (int i=1; i<n; i++)
 {
   vx+=(acceleration_x[i-1] + acceleration_x[i])/2.0f*dt;
   dx+=vx*dt;
 }

and similarly for dy and dz. Here

float acceleration_x[n];

contains x-acceleration values from start to end of measurement at times 0, dt, 2*dt, 3*dt, ... (n-1)*dt.

To find the total displacement, you just do

dl=sqrt(dx*dx + dy*dy + dz*dz);

Gyroscope is not necessary for this, but if you are measuring linear distances, you can use the gyroscope reading to control that rotation of the device was not too large. If rotation was too strong, make the user re-do the measurement.

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